I hit my dog in the nose?

My dog (boston terrier) were just playing around on the carpet and i accidentally hit his nose with my knee really hard ): i feel really bad because when i hit him he just slowly started moving away and squeeling a lot! and he was afraid of me. I pet him but i want to know if i really did any damage to his nose? he seems fine now, but hes really calm and when i try to play so he doesnt feel scared he does it a little bit, but i think hes stilled scared... please help!